DAC Switching Instant Calibration for Timing Error Correction
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Solution Overview
Problem
Conventional digital-to-analog converters (DACs) suffer from timing errors due to variations in switching instants of transistors, leading to degraded linearity and output errors, which existing technologies have not adequately addressed.
Innovation Solution
A calibration system is introduced that includes a second DAC to detect spurious spectral performance parameters in the output of the first DAC, generating an adjustment signal to correct timing errors by adjusting the switching instants of the transistors in the first DAC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional DACs are used without calibration, then the device complexity is low, but timing errors occur due to variations in switching instants of transistors
Solution Approach 1:
The calibration system performs timing error correction before the DAC is put into normal operation. A calibration signal is applied to the DAC, and the calibration system measures the actual switching instants of the transistors and generates adjustment signals to pre-correct the timing errors, so that when the DAC operates normally, the timing errors are already minimized.
Solution Approach 2:
The calibration system uses feedback to measure the actual switching instants of the transistors in the DAC and generates adjustment signals based on the measured timing errors. The adjustment signals are fed back to the DAC to correct the timing variations, creating a closed-loop system that continuously optimizes the switching timing.
2Measurement precision
If calibration system is added to correct timing errors, then timing precision is improved, but device complexity increases
Solution Approach 1:
The calibration system creates a model or copy of the DAC's switching behavior by applying a calibration signal and measuring the actual switching instants. This model is used to generate adjustment signals that replicate the necessary timing corrections without requiring direct modification of the original DAC circuitry.
Solution Approach 2:
The calibration system is designed to be multi-functional, serving both as a measurement device for detecting timing errors and as a correction device for generating adjustment signals. This universal approach reduces the need for separate dedicated components for each function.
3Manufacturing precision
If adjustment signal is applied to correct timing error, then output quality is improved, but measurement and detection difficulty increases
Solution Approach 1:
The calibration system introduces an intermediary calibration signal that facilitates the measurement of switching instants. This calibration signal serves as a mediator between the input signal and the output, enabling precise measurement of the transistor switching times without requiring direct observation of the internal switching nodes.
Data Source
AI summary
An apparatus for calibration of a signal converter is disclosed. This apparatus includes a first digital-to-analog converter (“DAC”) and a calibration system coupled to an output port of the first DAC. The calibration system includes a second DAC. The calibration system is configured to provide an adjustment signal responsive to a spurious spectral performance parameter in an output of the first DAC. The spurious spectral performance parameter is sensitive to a timing error associated with the first DAC. The calibration system is coupled to provide the adjustment signal to the first DAC to correct the timing error of the first DAC.